Glow plug



Oct. 19, 1937. H, RABEZZANA 2,096,198

GLOW PLUG Filed Oct. 5, 1936 9Qc20? Wadezzaiza Patented Oct. '19, 1931 7 V v r V UNlTED STATES PATENT OFFICE GLOW PLUG Hector Rabezzana, Flint, Mich, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application October '5, 1936, Serial No. 103,977 Claims. (01. 123-145) My invention relates to incandescent igniting and the second being provided for holding the devices designed to ignite the combustible miX- insulating member within said passage by a gland ture in Diesel and similar internal combustion nut it! which is in threaded engagement with engines at starting, and for a short time after the upper end of said passage. Suitable gaskets the engine begins to operate; such devices being M, ii are provided between the lower shoulder l 5 commonly referred to as glow plugs and being and the ledge 9, and between the upper shoulder characterized by the fact that they include a 8 and the inner end of the gland nut H], in order heating element of high resistance which is to prevent leakage of gases from within the enheated to incandescence by a current of elecgine cylinder past the insulating member as will tricity of low voltage, ordinarily six volts or less. be understood. a 10 The object of my invention is to improve and The numerals l3, l4 designate electrodes exsimplify and reduce the cost of such glow plugs, tending through passages in the insulating memwhile at the same time enhancing their eifiher and through which current is supplied to a. ciency for the use for which they are required; coil l5 of high resistance metal and whereby to which end my invention contemplates a glow the latter is heated to incandescence, the coil 15 plug wherein the customary outer shell or casing being within the engine cylinder so that the for the insulating member thereof is made unmixture to be ignited comes into contact therenecessary, and is dispensed with, as well also as with. The electrodes are insulated'from one 7 a glow plug having improved and more efficient another by the material of the insulating memmeans for connecting the current supply conher and the interstices between them and the pas- I ductors to the plug. sages through which. they extend are filled by 20 With the above and other objects of invention suitable cementations or equivalent material [5, in view my invention consists in the improved 5. These ele t es are m fi & 5 0 C 1- glow plug illustrated in the accompanying drawducting metal, such as copper, and have enlarged ing and hereinafter described and claimed, and heads l1, I8 housed Within recesses provided in 25 in such variations and modifications thereof, the lower end of the insulator 6; and. their upper within the scope of the concluding c1aims,as will ends are upset, as at I9, 20, to hold them within be obvious to those skilled in the art to which the passages provided for them and permanently my invention relates. assembled with the insulating member. The In the drawing accompanying .and forming a ends of the igniting coil I5 are welded, brazed 30 part of this specification and wherein the preor otherwise fastened to the heads H, H! as will" ferred form of my invention is illustrated: be understood. I

Figure 1 is a view showing a section thereof Suppo abOVe the upper End f he insulatupon a longitudinally extending central plane, of ing member 5 is a head 2! made of moulded a glow plug made in accordance with my ininsulating material such, for'example, as bake- V35 vention. e lite, the same having a depending part or'skirt Figure 2 is a View showing the current supply 22 which fits closely about the upper end of connecting means of my improved glow plug in the insulating member but is not ordinarily plan, as seen from a position above the same. permanently fastened thereto; and the numerals 40 Figure 3 is a view similar to Figure 2 but show- 23, 24 designate internally threaded tubular in 40 ing the current supply connecting means in side serts about which the material of the head is elevation. moulded, and whereby they are permanently as- In the drawing, the numeral 4 designates'a sociated with the head. The numerals 25, 2B portion of the wall of the cylinder of an internal designate metallic clamps having projections 27, 5 combustion engine, the head thereof in the more 8 secured to their lower ends by being riveted usual practice, and which wall has a passage 5 thereto, and which p jections extend through leading into the interior of the cylinder and holes in the depending skirt and the insulating within which my improved glow plug is received member and into engagementwith the electrodes and housed. The plug itself comprises an in- I3, M, as shown, thereby providing a conducting sulating member 6 made of porcelain or like path between the clamps and the electrodesand 50 ceramic material, or of mica, or in fact of any at the same time holding the head 2| in place suitable insulating material, the same being enupon the upper end of the insulating member, 6. larged at its central portion and having lower The numerals 29, 30 designate curved abutand upper shoulders 1 and 8 the first resting ments, made commonly of metal, the same being upon a ledge 9 provided within the passage 5, secured to the upper end of the head 2| by being moulded therein; and 31, 32 are bus bars or equivalent conductors through which current is supplied to the electrodes l3, 14 through i the clamps 25, 26 and the projections 21, 28,

these conductors being clamped between the upperends of the clamps and the abutments,

29, 30. i The clamping action of the clamps is produced by screws 33, ,34 extending through holes therein and the inner ends of which are in threaded engagement with the internally threaded inserts 23, 24; and theupper ends. of said clamps are bifurcated so as to provide two branches 3 5, 35, whereby three-point contacts are provided by the branches at the upper ends of the clamps which bear against the bus bars '31, 32 and the projections 2",28 at their lower ends which engage the electrodes l3, 14.

Having thus described and explained my invention I claim and desire to secure by Letters Patent: i V

l.'A glow plug comprising an insulating member; two electrodes extending through passages insaid insulating member and whereby current is supplied to an, igniting element at the inner end thereof; a head formed from insulating material, and which head is supported upon the outeiyend of said insulating member; two metallic clamping members supported upon op- ,posite sides of said head and having projections at their lower ends which engage said electrodes, and the upper ends of which members engage two currentsupply conductors and clamp them against said head; and screw mechanism between the ends of said clamping members for drawing them towardsaid head.

2. A'glow plug comprising an insulating member having an enlarged central part, and shoulders at the ends of said central part whereby said member may be secured in place within a passage in a cylinder wall; two electrodes extending through passages in said insulating member and whereby, current is supplied to an igniting element at the inner end thereof; a head formed of insulating material,;and which head is supported'upon the outer end of said insu1ati member; and means for clamping two current supply conductors against opposite sides of said head andfor establishing a conducting path between said supply conductors and said electrodes. i

3. A glow plug comprising an'insulating member having an enlarged central part, and shoul- 4; ,A glow plug comprising an insulating mem- 7 ber; two electrodes extending through passages in said insulating member and whereby current is supplied to an igniting element at the inner endthereof; a head formed from insulating material, and which head has a depending skirt at its lower end which surrounds the outer end or said insulating member; two metallic clamping members supported upon opposite sides vof said head and each of which has a projection at. its

lower end which extend'sthrough a hole in said skirt and into engagement withone of the electrodes aforesaid, and the upper ends of which clamping members engage 'two current supply conductors and clamp them against said head;

and'two screws, one associated with each of said clamping members, (and which screws act to draw said clamping members toward said head,

5. A glow plug comprising an insulating member; two electrodes extending through passages in said insulatingmember and whereby current is supplied to an ignitingvelement' at the inner end thereof; a head formed from moulded insulating material, and which head has a depending skirt at its lower end which surrounds the outer end of said insulating member; two metallic clamping members supported upon opposite sides of said head and each of which has a projection at its lower end which extends through a hole in said skirt and into engagement with one of the electrodes aforesaid, and the upper ends of which clamping members engage two current supply conductorsand clamp them against said u head; and two screws, one associated with each of said clamping members, and the inner ends of which are in threaded engagement with internally threaded sleeves embedded in said head. I

HECTOR RABEZZANA. 

